Plants are slowing climate change, but can't stop it: study
As human activity puts more carbon dioxide in the atmosphere, plants have responded by ramping up photosynthesis, a new study has found. While this may help slow climate change, it isn’t happening at a fast enough rate to stop it.
According to the study, which was published in the journal Nature on Wednesday, global photosynthesis increased by 12 per cent between 1982 and 2020, while global carbon dioxide concentrations grew by 17 per cent.
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“This is a very large increase in photosynthesis, but it’s nowhere close to removing the amount of carbon dioxide we’re putting into the atmosphere,” environmental scientist and lead author Trevor Keenan said in a press release. “It’s not stopping climate change by any means, but it is helping us slow it down.”
Photosynthesis is the process by which green plants use carbon dioxide, sunlight and water to create oxygen and their own food. Increased carbon dioxide in the atmosphere from human activity has long been linked to global climate change.
The international team of researchers behind the study was led by Lawrence Berkeley National Laboratory and UC Berkeley in California, with support from NASA and the U.S. government’s Department of Energy. They were able to assess changing global photosynthesis rates by comparing historical estimates and satellite imagery with models of how carbon is exchanged between the atmosphere and land.
Keenan, who is a scientist at Berkeley Lab and an associate professor at UC Berkeley, highlights the need to protect natural “land sinks” like forests, which capture carbon dioxide from the atmosphere.
“We don’t know what the future will hold as far as how plants will continue to respond to increasing carbon dioxide,” he said. "We expect it will saturate at some point, but we don’t know when or to what degree. At that point land sinks will have a much lower capacity to offset our emissions. And land sinks are currently the only nature-based solution that we have in our toolkit to combat climate change.”